Ratchet clutch for drive mechanism



C. W. ANDERSON.

RATCHET CLUTCH FOR DRiVE MECHANISM.

APPLICATION FlLED- MAY 28, 1919.

1 AQS, 1 72. atent d uly 18, 1922.

Application filed May 28,

To all whomz't may concern; Be- 't known that I, CHARLES W. ANDER- soN, residingat Brooklyn, in the county of Kings and State of New York, lime invented certain new anduseful Improvements in Ratchet Clutches for Drive Mechanism,- of which. the following is a specification.

This-invention relates to a ratchet clutch for drive} mechanism and is particularly adapted for'use in connectionwith hodelevators and the like. L

The invention herein ,shownand described is an improvement over the structure disclosed in myv pending application Serial No. 161,344, filed April 11,1911. -"A particular object of the present .im:

- provementisto provide abeltstightener in i will not, at any time,

which likelihood of unduestress .ybeing placed upon the belt during operation is avoided, to theend that the effective life of the'beltmay be prolonged and thegeneral efficiency of the belt-tightener improved.

. A more; detailed object isto provide a clutch mechanism of such construction that the belt-tightening roller controlled thereby be maintained by the clutchin its position of maximum tightness. A. further detailed object. is to provide a clutchwhich,Iwhile it is effective at all times to compensate for anystretching ofthe belt rluring use, will at the same time afford a deas an ideal degree.

sirabledegree of lost-motion which will permit the belt-tightening roller to assume,-xduring the operation ofthe device, only ade'gree of tightnessawhichlmay be here referredto Other objects andaims of theinvention, more or lessispecific than those referred to above, will be in part obvious and in part pointedout in the'course of the following description, of the; elements, combinations, arrangements of parts andapplications of principles, constituting the invention; .and the scope of protection contemplated will be indicatedin the appended claims.

In the; accompanying drawings which are l to betakenas a part of'thisspecification,

and in, which I have shown merely a preferred form of em bodiment of the nvention:

.Fig. lis a side elevational-view of a belti tightening device forhod elevators, the same being shown as constructed along the general linesas that illustrated inthe copending application above referred, to, and illustrating a clutch mechanism inassociation therewith a stares CHARLES w. uvnnnson, or nnoonnvn, NEW YORK I ,RATOHET CLUTCH roannivn MECHANISM L Specification of Letters r tentg Pateritedduly18,1922.

1919. ..Serial No. 300,303. I

gonstructed in accordance with this inven- 1on.- 1

.F1g. 2' is a vertical sectional View taken upon the plane of line H of Fig. 1. r

- F g. 3 is, anenlarged detail sectional view taken. upon the plane of line III of Fig. 1, I

and i is a diagrammatic view for illustrat ngdifi'erent positions of parts of the clutch ;m echanism. 1 i Referring to the drawings for describing in detail the structure which .isillustrated therein, thereference character-L indicates a motor having a drive shaft 1 and a drive pulley 2. I i i reference character shaft carrying a pinion 3 for engaging the drive gearrt ofa hod elevator or thelike, said shaftGalso carrying a'pulley 5 to be driven from the pulley 2.

slack belt H extends between thepul leys '2 iand'. Y

Thebelt-tightener includes a body member 6 which. is mounted to oscillate upon a fixed shaft 17 arranged substantially parallel to theshafts 1 and G, and adapted to hang below saidrsha ft G. At its lower end the bodyv member 6 is provided with a belttightening roller 8 which is mounted upon a pin Qentending betweenspaced arms 10, of said member 6. U

.Normally,the;;roller 8 hangs free of the belt H. Any suitablemeans may be employed for swingingthe roller manually into engagement with the belt when desired.

in 'my. copending applications Serial 'No.

161,8 li and SerialyNo. $00,304:, the former illustrating a; hand control, and the latter illustrating afoot lever control similar to that shown in Fig.2. 'Thelever, in Fig.2, is indicated :bythe reference numeral 11.. It is pivotally-mounted, as at 12, and has a pin 13 engaging withina'slot 14: formed in one of the arms. 10 in. such relation that downward pressure upon the outer end 15 of the lever will swing. the; roller 8 forcefully against thev belt. A spring, or other suit-, ablemeans, as 16,1naybe arranged to normally retain the end 15 of. the lever elevated sothatthe roller will not press against the belt.

Due to the slaclrness of the belt H, no motion is'transmitted from the pulley 2 to the pulley 5, except 'wl'ien the roller 8 is pressingagainst the belt.

G. indicates a l 20 for engaging the teeth 18.

The body member 6 is provided with a clutch member 17 atoneside ,thereofponcentric with the shaft, the outer face of the clutch member being formed with suitable, ratchet teeth 18 thereon.

A, cooperating clutch member 19 is, mounted upon the shaft 7 to slide longitudinally thereon toward'jand away from the clutch member 17, the opposing face of the clutch member 19 being provided with teeth A ping21, carried by theclutch .member 19, extends transversely through a: slot 22 -forn1ed 1 in the shaft7- The pin isof-such width: relative to the, width of the slot, as to peimit a limited rotary movement of the clutch member 19 about the shaft 17 thusproviding a certain; desirable degree oflost motion as between the teeth of the clutclr members ,17 and 19, 1 i i spring 23 is interposed between the clutchimember 19 and the opposing-face of the adjacent support 2 1 of the shaft adapted to urge the clutch member 19 at all times toward and intoengagement with the'clutch member 17.

Any desired means maybe employed for moving the clutch member 1 g inst the pressure of the spring 23,, as occasion may require: An example of such means is illus-V trated herein and conforms in principle: to the structure disclosed in the copendin application' Serial No. 161,344. It inc udes a smallarm 25 pivotally mounted at one end of the shaft 7 and being connected by a link 26 with the pin 21, said link 26 being extended longitudinally of the shaft 7 through a central bore 27 formed in said shaft-1th receive it. The arm 25 carries achain, or link, 28 which extends into connectionwith an automatic control lever 29 byJVhlCh the arm may be automatically swung to pull back the clutch member 19 whenever the control lever 29 is lifted.

When the roller 8 is-in belt tightening position, and the clutch; members 117 and 1'9 are in engagement withfieach other, said clutch members will positively retain the roller 8 in engagement: with theibelt until the clutch member 19 is drawn backwardly. As soon as the clutch member 19 is drawn backwardly, however, the roller will immediately fall away from the belt and the driving connection between the pulleys 2 and 5 will be broken, and the dr1v1'ng con: nection will remain broken until the roller I is again swung into tightening position.

The lost motion aboveflreferred to between the-clutch members 17 and ,19 is of great importance in that it constitutes the means above referred to for preventing the main tenance of undue pressure of the roller 8 against the belt during the operation of the device. By referringtofFigs. 3 and 4 it will be seen that whenever the roller is swung toward the belt the frictional engagement of theteeth of the clutch member 17 with the teeth of the clutch member 19 will, of course,

cause, the zclutch member 19 to rotate with the clutch member 17 until the rotation of the clutch member 19 is arrested byengaigemoving now inthe opposite direction, will engage the teeth of the clutch member-19; The clutch member 19swill not immediately arrest returnhmovement of the clutch member 17 owingtothelostanotion of the clutch member 19. The clutch: member 19 will rotate-withthe clutch member 17 until the pin 21 has returned-to its first position Within the slot 22,that is,ffrom the position shown by dotted linesinFigs, 3 and 4, and the posl tion shownbyfull lines in'said figures. At this point the backward movement of the roller8 willbe arrested, and it is intended that i the point, or position-, in which backward movement of-the roller -8 is arrested is such as'to mainta-inan ideal. degree of pressure-against the belt, that, is, a degree-of pressure which is ample for transmitting the desired power fromthe pulley 2 to the pulley5 while at "the same time applying no unnecessary strains to the belt.

It willg of course, be seen that the-effectiveness of the lost =motion' above-referred to for producing the; results described, is equally present :regardless of whether the belt beia-new one, and therefore-relatively tight, or an old one, and thereforestretched and relativelyloose- If the belt is old and quite loose, theroller- 8 wilIi'simply sWing further before reaching its maximum tightness, and the clutch member '17 will rotate so as to step up anothertooth-or two relatively to the clu'tchumember 19. as many changes could bemade in this construction without departing *fromthe scope of the invention as defined-in the fol lowing v claims, it'is intended that all ma'tter contained in the above description or shown in the accompanying drawings,'- shall be able into and out of belt-tightening position, of means whereby to retain the belt-tightener in belt-tightening position, and said means comprising parts cooperative to retain, the belt-tightener only at a degree of tightness which is less than its maximum tightness.

'2. The combination with a drive pulley, a driven pulley, a slack belt extending between said pulleys, and a belt-tightener movable into and out of belt-tightening position, of means to manually move the belt-tightener into a position of maximum tightness, and lost motion retaining means for the belttightener adapted to retain the belt-tightener onlyat a degree of tightness which is iess than the maximum tightness.

3. The combination with a drive pulley, a driven pulley, a slackbelt extending between said pulleys, and a belttightener movable into and out of belt-tightening position, of a clutch for retaining the belt-tightener in belt-tightening position, said clutch comprising a pair of interengaging clutch members one carried by the belt-tightener and the other mounted to have a degree of lost motion whereby the clutch is effective only to retain the belt-tightener at a degree of tightness which is less than its maximum tightness.

4. The combination with a drive pulley, a driven pulley, a slack belt extending between said pulleys, and a belt-tightener movable into and out of belt-tightening position, of a shaft upon which the belt-tightener is pivotally mounted to swing, the clutch member slidably mounted upon said shaft to move into and out of engagement with said belt-tightener adapted, when in engagement with the belt tightener to retain the belttightener against unlimited swinging in one direction, and means whereby said clutch member is permitted a limited degree of rotation about said shaft, whereby said clutch member is capable only of retaining the belttightener at a degree of tightness which is less than its maximum tightness.

5. The combination with a drive pulley, a driven pulley, a slack belt extending be tween said pulleys, and a belt-tightener for said belt, said belt-tightener comprising a pivotally mounted body member having a portion arranged to swing into and out of tightening position against the belt, a shaft upon which the body member is pivotally mounted, and means to manually move the belt-tightener against the belt at will, of a clutch member carried by the body member having a toothed surface portion arranged substantially concentric with said shaft, a cooperating clutch member mounted to slide upon said shaft and having a toothed surface for engaging the toothed surface of the first clutch member adapted to cause the two clutch members to move together, and means interengaging between the shaft and the second clutch member of a character to afford a limited rotary movement of the second clutch member about said shaft for the purpose set forth.

In testimony whereof I aliix my signature in the presence of two witnesses.

CHAS. W. ANDERSON.

Witnesses L. Gnssroun HANDY, E. W. HAVILAND. 

